1. Field of the Disclosure
The disclosure relates to a laser welding tool for producing a weld seam to join work pieces wherein the laser beam can be moved along the weld seam using a linear drive.
2. Prior Art Discussion
Resistance welding is still the dominant process used in the automotive industry mostly using robot-guided welding tongs. Resistance welding is a welding process for electrically conductive materials based on the Joule heat of an electric current flowing through the joint. The Joule effect heats the work pieces to be joined until they melt. The welded joint is created when the molten material re-solidifies. The work pieces to be joined are usually pressed together using welding tongs during and after the current flow, which helps generate a homogeneous joint. Laser beam welding is gaining importance as an alternative process. Laser beam welding is mostly used for welding work pieces together that have to be joined with a narrow weld seam and low thermal delay. Like resistance welding, laser beam welding or laser welding is performed without adding another material.
The work piece surfaces of the abutting edges or the abutment of the work pieces to be welded is in the immediate vicinity of the focus of the collimator that is also called the cross-over point in laser beam welding. The typical diameter of the cross-over point is between 0.5 and 1.0 mm, which produces very high energy concentrations. As it absorbs the laser output, temperatures on the work piece surface rise extremely fast above the melting temperature of the metal so that a melt is formed. However, the advantages of laser beam welding are put into perspective by high acquisition costs, low efficiency and a considerable outlay for safety equipment. In addition, the gas or solid-state laser welding apparatuses currently used in industrial applications have fairly large dimensions and are not suitable for use in the automotive industry. An example of a laser welding system wherein the laser beams can be moved along a weld seam using a linear drive is known, for example, from JP 2004-243393.
A need therefore exists for a fiber laser welding tool that can be integrated into existing infrastructures for resistance welding and in particular facilitates the continued use of existing component tools and handling equipment for welding tools.
A further need exists for a fiber laser welding tool that ensures the required safety of people at a laser welding output typical for automotive applications (up to 2 kW) and reduces design-related disadvantages of industrial welding tools, in particular high acquisition costs, poor efficiency, and considerable expenses for safety equipment.